Fabricated bedplate structure for a machine

ABSTRACT

A fabricated bedplate for rigidly supporting a machine, especially a unitary turbine-generator power plant, in which the main strength member is a plate member having a cross section which is a segment of a circle. Transverse support members are welded to the main strength member to stiffen the latter against deformation from its circular shape.

United States Patent 91 Gate et a1.

[ June 26, 1973 FABRICATED BEDPLATE STRUCTURE FOR A MACHINE [75] Inventors: James M. Gate, Saratoga; Allen D. Levy, Sunnyvale; Louis Nunez, Jr., Los Gatos, all of Calif.

[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Oct. 26, 1971 [21] Appl. No.: 192,469

[52] U.S. Cl 290/52, 290/1, 248/19, 415/29 [51] Int. Cl. H021: 7/18 [58] Field of Search 248/19; 415/219, 415/131; 290/52, l, 2

[56] References Cited UNITED STATES PATENTS Hoffman 290/52 1,631,619 6/1927 Buvinger et a1 248/19 2,511,854 6/1950 Kane 3 ,05 2,400 9/ 1 962 Holpfer 2,733,029 1/1956 Griffith 2,538,228 1/ 1 951 Blair 2,531,178 11/1950 Van Nest 290/52 Primary Examiner-G. R. Simmons Attorney-A. T. Stratton [57] ABSTRACT A fabricated bedplate for rigidly supporting a machine, especially a unitary turbine-generator power plant, in which the main strength member is a plate member having a cross section which is a segment of a circle. Transverse support members are welded to the main strength member to stiffen the latter against deformation from its circular shape.

9 Claims, 4 Drawing Figures PATENTED JUN 2 6 1973 SHEHZUF'Z FIG.4

FABRICATED BEDPLATE STRUCTURE FOR A MACHINE BACKGROUND OF THE INVENTION Unitary or package turbine-generator power plants, such as employed in marine vessels for auxiliary shipboard electrical power, comprise a bedplate or frame upon which are mounted a steam turbine, an electrical generator, reduction gearing between the turbine and generator, and a steam condenser connected to the exhaust of the turbine.

The turbine and generator are disposed in mutually parallel axial alignment with each other and usually are connected to the reduction gearing by suitable coupling devices. Accordingly, the turbine speed is reduced to a suitable speed for driving the generator, for example, 900, 1,200, 1,800 or 3,600 R.P.M.

During operation on shipboard, the ships structure is subject to substantial deformation and the bedplate must be sufficiently rigid to withstand the distorting forces imposed thereon and prevent transmittal of such distorting forces to the bearings of the power plant. Accordingly, the bedplate must maintain the accuracy of alignment of the bearings and the gearing in order to prevent undue wear and damage thereto, as well as to minimize objectionable gear noise in the reduction gearing.

Notwithstanding the above severe requirements and demands on a bedplate of this type, it is highly desirable (if not essential) to make the bedplate as light and compact as possible, in order to minimize the weight of the power plant and minimize the space required (both at a premium on marine vessels).

However, to attain the required rigidity, bedplate structures heretofore have usually employed I-beams and/or channel members as the main support or stiffening members, thus requiring considerable material and weight with extensive welding of seams and joints.

In view of the above, one of the main objects of the invention is to obviate the provisions of channel members and/or l-beams as the main support members in a bedplate structure of this type.

Another object is to provide a fabricated bedplate of the above type in which the main support or strength 7 is provided by a plate member that is bowed to an arcuate shape, thereby to impart greatly increased rigidity to the plate member, when compared to a flat or planar plate member.

BRIEF SUMMARY OF THE INVENTION In accordance with the invention the bedplate is fabricated with a main strength member of sufficient size and shape to accommodate the turbine, reduction gearing and the generator. The main strength member is a sheet metal or metal plate member bowed to an arcuate cross section, for example, in the form of a segment of a circle, with its convex surface facing upwardly and its concave surface facing downwardly.

A plurality of transverse plates are welded to the concave surface of the main strength member to stiffen the latter against deformation from its bowed circular cross section.

The main strength member is provided with three cut-out portions of predetermined size and shape to accommodate the machine components, such as the turbine exhaust outlet structure, the reduction gear casing and the electrical generator. Suitable flange members may be welded to the main strength member adjacent the cut-out portions to permit attachment of the associated machine components thereto.

Accordingly, there is provided a unitary fabricated bedplate structure that is formed essentially of light weight plate members arranged in a manner to provide a highly rigid structure sufficient to minimize transmittal of deforming stresses to the machine components, thereby preserving the carefully adjusted factory alignment of the shaft, bearing and coupling components of the machine.

THE DRAWINGS The invention and the objects and the advantages thereof, will be better understood upon consideration of the following detailed description read in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of a unitary turbinegenerator power plant having a bedplate formed in accordance with the invention;

FIG. 2 is an isometric view of the bedplate shown in FIG. 1;

FIG. 3 is a bottom view of the bedplate; and

FIG. 4 is an end view of the bedplate.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in detail, FIG. 1 shows a unitary electric generating power plant 10 comprising a bedplate 12 formed in accordance with the invention and having mounted thereon a prime mover such as a steam turbine 14, an electrical generator 16 driven by the turbine 14 and reduction gearing l8 interposed between the output shaft 20 of the turbine and the shaft 22 of the generator 16.

The steam turbine is provided with suitable throttle control mechanism 24 for controlling flow of pressurized motive steam admitted thereto through an inlet conduit 26 from any suitable supply (not shown).

Also, as well known in the art, the exhaust hood structure 28 of the turbine is connected to a steam condenser 29 (only partially shown) by a tubular expansion conduit structure 30.

The turbine 14 is operable at a considerably higher speed than required by the generator 16. For example, if the generator produces A. C. at cycles/sec. and has two poles, its speed should be maintained at 3,600 R.P.M., while the turbine may have a rated speed of about 5,000 to 7,000 R.P.M. The reduction gearing 18 is effective to convert the speed of the turbine output shaft 20 to the above-required speed for the generator rotor 22.

In view of the high speeds involved and the necessary speed reduction required, the rotating components of the turbine 14, the generator 16 and the reduction gearing 18 must be very accurately aligned with regard to their axes of rotation to prevent undue wear in their support bearings (not shown).

Accordingly, the bedplate 12 is made and formed in accordance with the invention to have a high degree of rigidity and/or resistance to deformation and lightness in weight. The bedplate 12, as best seen in FIGS. 2, 3 and 4, comprises a sheet metal or plate member 32 of generally rectangular peripheral shape in plan and bowed to an arcuate cross-sectional shape (FIG. 4). The plate member 32 acts as the main strength member of the bedplate and is somewhat larger in length and width (in plan) than the turbine, generator and reduction gearing aggregate (note FIG. I for the length aspect and FIG. 4 for the width aspect).

The main strength number 32 is disposed with its convex surface 33 facing upwardly and its concave surface 34 facing downwardly and is maintained precisely in its arcuate shape by a plurality of axially spaced, parallel plate members 36, 37, 38 and 39 disposed in the bight of the concave surface 34. The plate members 36 and 37 have outer arcuate edges 36a, 37a, conforming to the shape of the concave surface 34 and are disposed in contiguous abutment with the concave surface 34 and extend transversely across the plate member in a chordal manner.

The plate members 36 and 37 are rigidly connected at their edges 36a, 37a, by continuous welding joints to the main strength member 32.

On the other hand, the plate members 38 and 39 extend upwardly through an opening 41 in the strength member 32 and cooperate with a pair of opposed plate members 42 and 43 to form at least the lower casing portion 45 for the reduction gearing 18. The lower gear casing portion 45 is provided with a peripheral flange 46 having a semi-circular groove 47 to accommodate the output shaft of the reduction gearing I8 and a semicircular groove 48 to accommodate and support the output shaft 20 of the turbine. The groove 48 is extended in axial direction and augmented by a semicylindrical flanged member 50 connected to the transverse plate member 38 in cantilever fashion and buttressed by an upright support plate 51 abutting and conforming at its lower edge to the upper (convex) surface of the strength member 32 and welded thereto by a continuous seam welded joint 51a.

The main strength member 32, as best seen in FIGS. 2 and 3 has a portion of its arcuate surface cut away from a medial plane defined by the stiffening chordal plate 39 to the right edge 32a of the member 32 to form a rectangular opening 53. The opening 53 is bounded on its diametrically opposed edges by vertically extending plates 54 and 55.

Accordingly, the right-hand portion of the strength member 32 (as viewed in FIGS. 2 and 3) is discontinuous in transverse direction because of the opening 53 and may be deemed to comprise a pair of elongated arcuate arm portions 32c and 32d integral therewith and in opposition to each other.

As best seen in FIG. 3, the arcuate portion 320 is stiffened by a plurality of spaced arcuate plate members 57a, 57b, 57c and 57d while the arcuate portion 32d is stiffened by a plurality of arcuate plate members 58a, 58b, 58c and 58d.

The bottom portion of the bedplate 12 is boxed in from the transverse plate 37 to the plate 39 by a rectangular bottom plate 59 seam welded about its periphery in a fluid tight manner to the plates 37 and 39 and to the strength member 32. Accordingly, a fluid tight chamber 60 is formed thereby that is in communication with the lower gear casing portion 45. This chamber may be employed as a reservoir for containing the lubricating oil for the lubrication requiring components of the turbine-generator set 10, such as the reduction gearing l8 and the turbine and generator bearings (not shown).

In a similar manner, the bottom portions of the opposed arms 32c and 32d are boxed in from the transverse plate 39 to the stiffening plate 7c by a seamwelded rectangular bottom plate 62, and from the transverse plate 39 to the stiffening plate 580 by a seam-welded rectangular bottom plate 63, respectively. All of the abutting surfaces of the plate members 57a 57d are seam welded to the arm portion 32c and the plate 54, and all of the abutting surfaces of the plate members 58a 58d are seam welded to the arm portion 32d and the plate 55 to form a rigid structure.

The thus boxed arm portions 32: and 32d are maintained in fixed predetermined spaced relation by a tubular spacer member 65 interposed therebetween in a direction transverse to the longitudinal axis of the bedplate and welded at its opposite ends to the vertical plates 54 and 55.

The vertical plates 54 and 55 are provided with a pair of elongated strip members 67, 68, respectively, welded thereto and disposed in a common horizontal plane, thereby to form support flanges for the generator 16 (see FIG. I). If desired, the flange members 67 and 68 may be stiffened by an axially spaced array of depending plates 70 and 711 (only one plate 71 shown), extending vertically and welded thereto and to the associated convex surface of the arm members 32c and 32d. The flange members 67 and 68 are substantially co-extensive with the opening 53 but the flange 67 is in endwise abutment with the plate 39 of the gear casing while the flange 68 extends beyond the plate 39 and is in lateral abutment with the side plate 43 of the gear casing (see FIG. 4).

The left end portion of the bowed plate member 32, as best viewed in FIGS. 2 and 4, is provided with a pair of vertically extending support columns and 71, welded thereto, for supporting the left end, i.e., the exhaust end, of the turbine 14 and may be provided with suitable pads or hearing plates 72 at their uppermost ends.

Also, a preferably circular opening 74 is cut out of the bowed plate member 32 to accommodate passage therethrough of the turbine exhaust duct 28. To further stiffen and support the bowed plate 32 adjacent the opening 28, a vertical plate member 75 extending axially on the longitudinal centerline of the bedplate I2 is welded to the transverse plates 36, 37 and to the inner or concave surface of the bowed plate member 32.

Referring now to FIG. 1, it will be seen that the bedplate 12 is so formed and arranged that the exhaust end of the turbine 14 is supported on the two support columns 70 and 71 while the steam inlet end of the turbine with its output shaft 20 is supported by the semicylindrical member 50 on the lower gear casing 45.

The electrical generator 16 is supported on the opposed elongated flanges 67, 68 with one end of its rotor received in the recess 47 of the lower gear casing. The reduction gearing 18 is disposed in the lower gear casing 45 with its input and output shafts in alignment with the turbine shaft 20 and generator rotor 22.

The above-described turbine-generator power plant It) is usually placed on a pair of axially spaced girders or beams 74 and 75 forming a part of the deck ofa marine vessel and extending transverse to the centerline of the bedplate 12. The bedplate is preferably supported at three spaced points, as well known in the art, to simplify installation and may be provided with three spaced pads 76, 77 and 78 (FIG. 3) for this purpose.

It will now be seen that a highly rigid, yet simple and light-weight bedplate has been provided which is highly suited for shipboard use and which may be subjected to twisting forces of the ships deck structure without imparting distorting stresses on the rotating components of 14, 18 and 16 mounted thereon.

Although only one embodiment has been shown, it will be seen that the invention is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

We claim as our invention:

1. A fabricated bedplate structure for rigidly supporting a turbine-generator plant including a turbine, a generator and reduction gearing interposed therebetween for driving the generator from the turbine, said bedplate structure comprising a plate member of arcuate cross section with its convex surface facing upwardly and its concave surface facing downwardly, and

a plurality of spaced support members extending in a chordal manner transversely in the bight of said concave surface and attached to said plate member to stiffen the plate member against deformation of said convex surface.

2. The structure recited in claim 1, wherein the plate member has openings of predetermined shape and size to accommodate the turbine, the generator and the reduction gearing.

3. The structure recited in claim 1, wherein the plate member has a central longitudinal axis, and

the turbine shaft, the generator shaft and the reduction gearing rotate about axes parallel to the axis of the plate member.

4. The structure recited in claim 3, wherein the support members are plates disposed in planes extending transversely to the axis of the arcuate plate members and having arcuate edges conforming to the concave surface and welded thereto along said arcuate edges.

5. The structure recited in claim 1, and further including a bottom plate member disposed below the arcuate plate member and the stiffening plates and welded thereto in a leakproof manner,

said bottom plate member cooperating with the arcuate plate member and the stiffening plate to form a liquid reservoir.

6. The structure recited in claim 2, wherein one of the openings extends from one end to a median portion of the plate member and forms a pair of opposed elongated arms of arcuate cross section,

each of said arms is provided with an axially extending flangemember, and

said flange members are effective to support the generator.

7. The structure recited in claim 6, wherein another of the openings is of substantially circular cross-section, is disposed adjacent the opposite end of the plate member, and is effective to accommodate passage therethrough of the turbine exhaust duct.

8. The structure recited in claim 6, wherein the opposed arms are maintained in predetermined spaced relation with each other by a transverse member interposed therebetween.

9. The structure recited in claim 2, wherein one of the openings has a pair of spaced plates extending upwardly therethrough transverse to the longitudinal axis of the convex plate, and

a pair of plates parallel to said axis extending upwardly from the convex plate,

said two pairs of plates jointly forming a lower casing 

1. A fabricated bedplate structure for rigidly supporting a turbine-generator plant including a turbine, a generator and reduction gearing interposed therebetween for driving the generator from the turbine, said bedplate structure comprising a plate member of arcuate cross section with its convex surface facing upwardly and its concave surface facing downwardly, and a plurality of spaced support members extending in a chordal manner transversely in the bight of said concave surface and attached to said plate member to stiffen the plate member against deformation of said convex surface.
 2. The structure recited in claim 1, wherein the plate member has openings of predetermined shape and size to accommodate the turbine, the generator and the reduction gearing.
 3. The structure recited in claim 1, wherein the plate member has a central longitudinal axis, and the turbine shaft, the generator shaft and the reduction gearing rotate about axes parallel to the axis of the plate member.
 4. The structure recited in claim 3, wherein the support members are plates disposed in planes extending transversely to the axis of the arcuate plate members and having arcuate edges conforming to the concave surface and welded thereto along said arcuate edges.
 5. The structure recited in claim 1, and further including a bottom plate member disposed below the arcuate plate member and the stiffening plates and welded thereto in a leakproof manner, said bottom plate member cooperating with the arcuate plate member and the stiffening plate to form a liquid reservoir.
 6. The structure recited in claim 2, wherein one of the openings extends from one end to a median portion of the plate member and forms a pair of opposed elongated arms of arcuate cross section, each of said arms is provided with an axially extending flange member, and said flange members are effective to support the generator.
 7. The structure recited in claim 6, wherein another of the openings is of substantially circular cross-section, is disposed adjacent the opposite end of the plate member, and is effective to accommodate passage therethrough of the turbine exhaust duct.
 8. The structure recited in claim 6, wherein the opposed arms are maintained in predetermined spaced relation with each other by a transverse member interposed therebetween.
 9. The structure recited in claim 2, wherein one of the openings has a pair of spaced plates extending upwardly therethrough transverse to the longitudinal axis of the convex plate, and a pair of plates parallel to said axis extending upwardly from the convex plate, said two pairs of plates jointly forming a lower casing for the reduction gearing. 